Master Cylinder (Brake) FAQ?

[PabloCruise]

I have take a look through the FAQ section, and ran a Search through the 40/55 section and not finiding what I want, so I'll start a new thread in the hopes that we can gather enough collective wisdom here on master cylinder options to warrant FAQ status for future queries.

I put a '76 axle under my '74 FJ55 to get the disc brakes. We left the '74 master cylinder in place and the combo has "adequate" stopping power, but the pedal effort is definitely higher than my '78 40 w/ disc/drum and original master.

I recently rebuilt the master on the '74 Pig and while I was in there I removed the front proportioning valve. I put everything back together and bled the entire system - no change in pedal effort. My concern is that the pedal effort is too high for the wife to do a full-on panic stop.

I'd like to get the same kind of pedal effort that I have with the '78 40, but I am having a hard time finding a resource that cross references what year used, what size diameter the bore is, what the original application was (drum/drum, disc/drum, or disc/disc) as well as the outlet orientation of the master cylinder (side/top/other?). If we could comper reservior configuration as well that would be a plus.

Anyone want to take the first stab at this?

 

[PabloCruise]

It looks like this may not be a topic of great interest?

 

[ken_79-fj40]

Is the master cylinder bore the same between a 74 and 76? I haven't played around much with cruiser brake conversions but I've played with them quite a bit on fox mustangs. If you don't have the caliper bore and master cylinder bore matched up pedal effort is going to be either soft or hard. If it's too hard now I would suspect the 76 master might have a smaller bore. When swapping masters you have to make sure the booster pushrod length is correct too.

 

[73tlcv8]

I have mini truck front discs and stock rear drums, mini truck booster and a fj60 master. This works well together. I noted my petal effort was higher after installing the 60 master, swapping the booster to the mini truck bendix unit worked for me.

 

[Josie'sLandCruiser]

Hi all,

When I bought my FJ40 (11/1973 manufacture date) in 1997 it still had four wheel drum brakes. In 2001 or so converted to front disc brakes using the front axle from a '78 BJ40 but retained the '74 drum brake booster & master cylinder. An improvement over the front drum brakes.

At some point the the brake booster died, but the rig would still stop, just with more effort. When I went to install rear disc brakes (2006?) I decided to do an new booster. Used a booster from a 1985 Toyota 4wd mini-truck, and the master cylinder from a 1989 4wd mini-truck. This combo works fine, no issues bolting everything up (except than the activator rod for the booster needed to be shortened slightly.)

So I would suggest upgrading the brakes, four wheel discs, 4Runner caliper, etc. An Iron Pig is a whole lot of metal to stop moving!

Regards,

Alan

 

[Howard705]

A Raybestos catalog has almost all this. Smaller MC bore=lower effort/longer travel. Larger dia/tandem booster=lower effort. Larger caliper piston/wheel cyl bore (if there are choices on these) =lower effort/longer travel.

 

[PabloCruise]

Is the master cylinder bore the same between a 74 and 76? I haven't played around much with cruiser brake conversions but I've played with them quite a bit on fox mustangs. If you don't have the caliper bore and master cylinder bore matched up pedal effort is going to be either soft or hard. If it's too hard now I would suspect the 76 master might have a smaller bore. When swapping masters you have to make sure the booster pushrod length is correct too.

I do not think so, but I am not sure...

Smaller bore = better for disc?

 

[PabloCruise]

I have mini truck front discs and stock rear drums, mini truck booster and a fj60 master. This works well together. I noted my petal effort was higher after installing the 60 master, swapping the booster to the mini truck bendix unit worked for me. View attachment 930259

Do you mean swapping the mini-truck booster lowered your pedal effort?

 

[PabloCruise]

Hi all,

When I bought my FJ40 (11/1973 manufacture date) in 1997 it still had four wheel drum brakes. In 2001 or so converted to front disc brakes using the front axle from a '78 BJ40 but retained the '74 drum brake booster & master cylinder. An improvement over the front drum brakes.

At some point the the brake booster died, but the rig would still stop, just with more effort. When I went to install rear disc brakes (2006?) I decided to do an new booster. Used a booster from a 1985 Toyota 4wd mini-truck, and the master cylinder from a 1989 4wd mini-truck. This combo works fine, no issues bolting everything up (except than the activator rod for the booster needed to be shortened slightly.)

So I would suggest upgrading the brakes, four wheel discs, 4Runner caliper, etc. An Iron Pig is a whole lot of metal to stop moving!

Regards,

Alan

Good to know about this fitment - thank you!

 

[PabloCruise]

A Raybestos catalog has almost all this. Smaller MC bore=lower effort/longer travel. Larger dia/tandem booster=lower effort. Larger caliper piston/wheel cyl bore (if there are choices on these) =lower effort/longer travel.

http://www.raybestosbrakes.com/magn....html?searchCategory=Automotive / Light Truck

Raybestos does not go all the way back to my '74 Cruiser. It does say that my '78 Cruiser, w/ disc fronts has a 7/8" MC. I believe my '74 Pig came w/ a 1" bore MC, so I guess smaller bore MC is more well suited for front disc.

 

[Howard705]

I have an old paper catalog. W

 

[Howard705]

Guess the really old stuff isn't online. I knew there was a reason I saved the old catalogs. I have more pages of clutch m/c s/c shoes/drums/calipers in here if you need it. This is the drum brake vehicle section. This is handy if you need to tell the parts guy what part numbers to order too.

 

[PabloCruise]

View attachment 957938 View attachment 957940 View attachment 957938 I have an old paper catalog. W

Thank you!

 

[73tlcv8]

Do you mean swapping the mini-truck booster lowered your pedal effort?

Yes, pedal efffort was pretty high with the fj40 booster. Pedal feel/effort is excellent now.

 

[PabloCruise]

Yes, pedal efffort was pretty high with the fj40 booster. Pedal feel/effort is excellent now.

Got it. What is the bore of your 60 MC?

 

[Howard705]

I'll get more pages on with '75-up

 

[PabloCruise]

I'll get more pages on with '75-up

That would add a lot to the thread, thank you!

 

[Poser]

If you want the brakes to be the same between the 40/55, then you will need to install the larger, dual diaphragm booster and disc brake master cylinder TJ.

 

[PabloCruise]

If you want the brakes to be the same between the 40/55, then you will need to install the larger, dual diaphragm booster and disc brake master cylinder TJ.

Thanks. I was trying to sort out the individual variables, looking at MC bore heavily as I do not have room for that big-a$$ booster w/ the 3FE swap.

 

[Poser]

Then it will be a compromise.